This invention relates to thermal storage and fluid cooling and, more particularly, to an improved method and apparatus for forming, storing, and utilizing ice on a plurality of tubular passageways passing throughout a pool of fluid stored in a vessel. Alternately, an improved method and apparatus are provided for cooling a fluid passing through the plurality of tubular passageways throughout a pool of fluid in a vessel.
Ice storage equipment which forms ice during off-peak energy periods and then melts ice to supplement as a supply of cold to further cool a working liquid is known, for example, from U.S. Pat. No. 4,831,831. One known form of such ice storage equipment utilizes a refrigerant liquid flowing through a plurality of parallel tubular passageways which themselves are submerged in a pool of freezable storage liquid such as water. The plurality of refrigerant channels are usually connected between inlet and outlet headers which receive and discharge the refrigerant liquid.
During the ice production cycle, the refrigerant liquid, usually an ethylene or propylene glycol solution, is provided from a mechanical refrigeration unit to the inlet header and then through the plurality of tubular passageways. Such flow of sub-freezing refrigerant acts to form ice from the pool of liquid, which is usually water, about the individual passageways. During the supplemental cooling cycle, the refrigerant liquid is circulated through the plurality of tubular passageways after the refrigerant has been warmed usually by passing through a heat exchanger in an air conditioning or cooling system. Such a refrigerant is in turn sub-cooled by passing through the ice surrounded passageways. The refrigerant in turn melts the ice surrounding the passageways.
The present invention also applies to fluid cooling arrangements, wherein fluid to be cooled passes through a plurality of tubular passageways immersed in a pool of liquid within a vessel. The pool of liquid itself is cooled, usually by the use of a cooling tower. In turn, the liquid passing through the plurality of tubular passageways is cooled by the indirect contact with the pool of cooled liquid. The arrangement of the plurality of tubular passageways in the fluid cooling arrangement is quite similar to the ice storage arrangement, except that it is usually desirable to have counter-current flow in the ice storage arrangement whereby uniform ice build-up is produced on the outside of the tubular passageways. In a fluid cooling arrangement, it is usually desirable to have completely parallel flow through the adjacent tubular passageways.
It is desirable to improve the efficiency of the coil arrangement and tubular passageways or coil arrangement in the pool of liquid by eliminating unnecessary header and inlet piping or manifold space and replacing such space with tubular passageways that contribute to the cooling capacity of the system.